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da ([personal profile] da) wrote2006-08-01 02:10 pm

Today's word is: dewpoint

Ugh. Record power consumption levels in Ontario. "The agency that monitors electricity use in Ontario has issued a power warning and is asking consumers to cut back on usage as demand soars. Terry Young, of the Independent Electricity System Operator, recommends consumers keep air conditioners in the 26 degree range, keep blinds and curtains closed and avoid using major appliances between 8 a.m. and 8 p.m." Roger.

[livejournal.com profile] melted_snowball mentioned dewpoint in his "gawds it's hot" post, and I still didn't understand it, so I did a little reading, so I might as well share my new-found knowledge. And that is: dewpoint is a good measure to use when you're talking about awful humidity. wikipedia was all about the formulae, but they pointed to a page by accuweather which spelled things out nicely (if you're willing to use Fahrenheit).

The dewpoint temperature is the saturation point of the air, or the temperature to which the air has to be cooled in order to get condensation. It's an absolute measure of humidity, versus relative humidity, which goes down as the temperature goes up (and the humidity stays constant). A dewpoint above 20 degrees C (70F or so) will feel quite humid, and above 26 C (80F) is sauna-like. It's currently 23 here, and I think it was close to 27 or 28 last night when I walked the dog at 10pm (very close to the temperature; which meant the humidity was about 100%; which explained why I felt like I was in an invisible fog bank. Ugh.)

Comfortable dewpoints are from 10C - 15C (50F - 60F). In that range, sweat will easily evaporate and remove heat from your body. As moisture in the air increases, sweating is less effective since the air's approaching saturated, and your sweat doesn't evaporate.

Humidex and its American cousin "Real Feel Temperature" (hey accuweather, isn't there a less dippy name for that?) are based on dewpoint.
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[identity profile] sfllaw.livejournal.com 2006-08-01 07:10 pm (UTC)(link)
It feels almost tropical, doesn't it?

[identity profile] da-lj.livejournal.com 2006-08-01 08:15 pm (UTC)(link)
That was totally what I was thinking last night.

I bet our tomatoes and basil are ecstatic. That is, if they're not baked to a crisp.

[identity profile] dcseain.livejournal.com 2006-08-01 08:40 pm (UTC)(link)
Tomatoes are indigenous to Mexico, specifically the Valle de Mexico and the southern coast. They're loving it.

[identity profile] melted-snowball.livejournal.com 2006-08-01 09:49 pm (UTC)(link)
Weren't they domesticated in S. America? (It's been a whlie since I knew this stuff at the tips of my fingers, but that's what I recall.)

[identity profile] dcseain.livejournal.com 2006-08-01 09:55 pm (UTC)(link)
Nifty, i done learned something. That was never covered in any of my Latin American history nor Spanish history courses, neither here, nor in Spain.

Apparently the Spanish spread them from western Aymará and southern Quechua areas very early on.

[identity profile] melted-snowball.livejournal.com 2006-08-01 09:58 pm (UTC)(link)
I just remember it because L. pimpinellifolium (and I'm sure I misspelled that...) is found in Peru.

(There was a remarkable paper that some biologists I was working with 6 years ago wrote where they found a single gene for which variation was responsible for half of the difference in fruit size between "pimp" (which has tiny fruits) and the big beefsteak tomatoes we eat nowadays.)

[identity profile] dcseain.livejournal.com 2006-08-01 10:02 pm (UTC)(link)
Go you! You spelled it right. I started out in recombinant DNA and plant tissue culture some years back. If you're able to track that down, i would be interested to read it. I'll do some digging also to see what i can find.

[identity profile] melted-snowball.livejournal.com 2006-08-01 10:06 pm (UTC)(link)
No problem...

Frary A, Nesbitt TC, Grandillo S, Knaap E, Cong B, Liu J, Meller J, Elber R, Alpert KB, Tanksley SD.
fw2.2: a quantitative trait locus key to the evolution of tomato fruit size.
Science. 2000 Jul 7;289(5476):85-8.
PMID: 10884229 [PubMed - indexed for MEDLINE]

[identity profile] da-lj.livejournal.com 2006-08-01 10:34 pm (UTC)(link)
Go go bioinformaticist.
:)

[identity profile] dcseain.livejournal.com 2006-08-01 08:38 pm (UTC)(link)
Here in DC, Humidex or more commonly, Heat Index is the preferred term. I've never heard of Real Feel Temperature. Frankly, that phrase makes little-to-no sense to me.

[identity profile] da-lj.livejournal.com 2006-08-01 08:53 pm (UTC)(link)
Ah, but according to wikipedia, heat index isn't the same as humidex, as it's based on relative humidity, not dewpoint temperature. *shrug*

I'd heard of "Real Feel Temperature" before, but it really sounds to me like... a marketing-term for life-like silicone body parts, or something.

[identity profile] ng-nighthawk.livejournal.com 2006-08-01 08:54 pm (UTC)(link)
Dewpoint 10.5, current temp 30C.

The desert southwest can be bearable, if you're on the northern edge and about a mile up from sea level. :)

[identity profile] da-lj.livejournal.com 2006-08-01 08:58 pm (UTC)(link)
Wow, I guess so. Even I could be OK with that. Probably.

...Las Vegas: 35C, dewpoint 1C. <-- it's a desert! Man was not meant to live there! (And this explains the misting stations that were scattered around outside. Too darn dry.)

[identity profile] melted-snowball.livejournal.com 2006-08-01 09:49 pm (UTC)(link)
If there were a job at CU, I'd probably be tempted.